Fluid treating centrifugal apparatus and methods



Nov. 23, 1965 B. G. cox 3,219,264

FLUID TREATING CENTRIFUGAL APPARATUS AND METHODS Filed May 11, 1961 2 Sheets-Sheet 1 IN VEN TOR. BRADLEY G. COX

ATTORNEYS BY M, zwm. var/m Nov. 23, 1965 5, ox 3,219,264

FLUID TREATING CENTRIFUGAL APPARATUS AND METHODS Filed May 11, 1961 2 Sheets-Sheet 2 23 8b ll FIG. 4

INVENTOR. BRADLEY G. COX

, /MM MWMM ATTORNEYS 3,219,264 FLUID TREATING CENTRIFUGAL APPARATUS AND METHODS Bradley G. Cox, Saginaw, Mich, assiguor to Baker Perkins Inc., Saginaw, Mich., a corporation of New York Filed May 11, 1961, Ser. No. 109,376 12 Claims. (Cl. 23313) This invention relates to apparatus and methods for treating fluids and more particularly the invention pertains to centrifuge devices for clarifying, mixing, or mixing and clarifying fluids of different densities.

It frequently is desirable or necessary to separate liquids, gases, or combinations thereof into their more dense and less dense components, or to mix more dense and less dense fluids together into a more or less homogeneous mixture, or to mix such fluids with one another to effect a chemical reaction and then clarify the resultant compositions according to their densities. It has been found that a simple and effective clarification of different density fluids can be achieved by introducing a mixture of such fluids to a rotating centrifuge having helical passages spiraling about the axis of rotation from one end of the centrifuge to the other, the centrifuge being rotated at such speed as to cause the more dense components to move radially outwardly and displace the less dense components radially inwardly. By feeding the fluids to spiraling passages, the fluids can be made to traverse the length of the centrifuge so as to permit the components of the fluids to be discharged from the passages and collected at the opposite end of the centrifuge.

The principles underlying fluid clarification in the manner described above can be applied to a modified centrifuge of the same general type, but constructed in a manner to permit fluids of different densities to be fed individually to the passages of the centrifuge for intermixing. The mixing of the different fluids takes place automatically during the flow of the fluids through the centrifuges passages if the more dense fluid is introduced to the radially inner passages and if the radially inner and radially outer passages communicate with one another. A turbulent condition can be created within the centrifuge to aid in thorough mixing of the different density fluids if the radially inner and radially outer passages are formed on spirals or helices of opposite hand.

Combined mixing and clarifying of two diflferent fluids can be achieved with a single centrifuge formed according to the invention by constructing one part of the centrifuge as a mixer in the manner described in the preceding paragraph and by constructing the remaining part of the centrifuge as a clarifier in accordance with the construction set forth in the second paragraph above.

An object of this invention is to provide continuous flow apparatus for clarifying fluids according to their densities.

Another object of the invention is to provide continuous flow apparatus for mixing fluids of differing densities.

A further object of the invention is to provide continuous flow apparatus for both mixing and clarifying fluids of differing densities.

Another object of the invention is to provide apparatus of the kind indicated which is capable of operation in either vertical or horizontal positions.

Another object of the invention is to provide such apparatus which tends to eliminate slippage between the fluids and itself.

Another object of the invention is to provide continuous flow apparatus of the kind described wherein the resident time of the fluids in the apparatus can be controlled.

A further object of the invention is to provide a con- United States Patent tinuous flow method of mixing, or clarifying fluids of different densities, or both.

Another object of the invention is to provide continuous flow apparatus of the character referred to which is economical to manufacture, easily assembled and disassembled for cleaning, and which is rugged and durable in use.

Other objects and advantages of the invention will be pointed out specifically or will become apparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings in which:

FIGURE 1 is a vertical, sectional view of apparatus constructed in accordance with one embodiment of the invention and particularly adapted for clarifying fluids according to their densities;

FIGURE 2 is a fragmentary, top plan view of the apparatus shown in FIGURE'l;

FIGURE 3 is a fragmentary view similar to FIGURE 1, but illustrating a modified form of the invention which is particularly adapted for mixing fluids; and

FIGURE 4 is a view similar to FIGURE 3, but illustrating a further modification of the apparatus which is particularly adapted for mixing separate fluids and then clarifying the components of the mixture according to their densities.

Apparatus constructed in accordance with the embodiment of the invention disclosed in FIGURE 1 comprises an elongate centrifuge 1 having an outer shell member 2 and an inner cylinder 3. The outer shell is tubular and has a cylindrical bore extending from one end to the other. The surface of the bore is helically threaded or grooved to present an undulating configuration having alternating roots 4 and nodes 5. The cylinder 3 has its outer surface similarly grooved or threaded so that it also presents an undulating configuration having alternating roots 6 and nodes 7. The node diameter of the shell 2 and the node diameter of the cylinder 3 preferably are substantially the same, with just sufficient clearance therebetween to permit the cylinder 3 to he slid into and out of the shell 2.

At one end of the shell 2 is an annular flange 8 on which an end hell 9 removably may be mounted by suitable means such as screws 10. The hell 9 includes a hollow shaft 9a extending therefrom. The other end of the shell 2 is provided with an annular wall 11 to which is joined a hollow shaft 12.

One end of the cylinder 3 is provided with a conical end wall 13 and the other end of the cylinder is provided with a flat end wall 14 to which is fixed a shaft 15. The shaft 15 is provided with an axially extending slot 16 and the end wall 14 is provided with a radially extending slot 17 for reasons which subsequently will be explained.

When assembling the parts '2 and 3 of the centrifuge, the cylinder 3 is inserted into the shell 2 from the flange 8 end thereof. Preferably, the number and pitch of threads on the shell 2 corresponds to the number and pitch of threads on the cylinder 3 so that the nodes 5 and 7 of the respective members can be brought into diametral alignment. To assure proper axial positioning of the cylinder within the shell, the end bell 9 may be provided with a number of inwardly extending lugs 18 adapted to engage the adjacent wall 13 of the cylinder and limit relative axial movement of the parts 2 and 3 in a direction towards the end hell 9. The space between the parts 9 and 13 comprises a fluid chamber 18a. Similarly lugs'lSb are provided on the wall 11 at the opposite end of the shell 3 and support the shell 3 in position.

In order to avoid any tendency of the nodes of either member to nest with the roots of the other member, a cylindrical baflle or sleeve 19 having an extremely thin wall may be interposed between the members 2 and 3 which the shafts 12 and 15 project.

at one end of the centrifuge. Suflicient space between the members 2 and 3 to accommodate the sleeve 19 may be provided by swaging the threads of the cylinder in the area of the sleeve an amount to correspond to the wall thickness of the sleeve. A similar baflle or sleeve 20 may be similarly mounted at the other end of the centrifuge, but in-this instance the sleeve preferably is carriedby an end cap 21 which fits over the end wall 14 of the cylinder 3. The cap is provided with a tubular extension 22 that receives the shaft 15.

When the cap 21 is seated on the cylinder 3, the slot 17 formed in the end wall 14 provides a passageway between the wall 14 and the cap 21 which communicates with the slot 16 between the part 22 and the shaft 15. Moreover, a space 23 is provided between the cap -21 and the end wall 11 of the shell 2 to form a passageway in communication with a clearance 24 which exists between the hub 22 and the hollow shaft 12. The diameter of the cap 21 is not as great as the diameter of the bore of the shell 2 and as a result there is provided a space 25 between the wall of the shell and the sleeve '20 which communicates withthe passageway 23.

The grooves formed on the members 2 and 3 correspond to one another both as to hand and pitch. That is, if the grooves formed in the bore of the shell 2 constitute a right hand thread at a particular pitch, the grooves formed on the cylinder'3 also should constitute a right hand thread at the same pitch. As a result, assembly of the parts 2 and 3 in the manner described will cause the roots 4 and 6 of the respective members to form passages or channels 26 spiraling about the axis of the centrifuge 1 from one end of the latter toward the other. Each passage 26 is composed of a radially inner part 26a and a radially outer part 26b which communicate with one another between the sleeves 19 and 20. In the zones of the sleeves 19 and 20, however, the passages 26a and 26b are separate from one another, although it should be understood that the baffles 19 and 20 may be perforated, if desired.

Means is provided for mounting the centrifuge for rotation about its longitudinal axis and comprises a housing 28having a cylindrical outer wall 29 joined at one end to an end wall 30 which is provided with an opening through which the hollow shaft 9a extends. Bearings 31 are interposed between the shaft 9a and the wall 30 and are retained in place by a nut 32 threaded on the shaft 9a and a retaining ring 33 secured to the wall 30 by suitable means such as screws 34. A seal 35 is interposed between the members 32 and 33 to make the journal fluid tight.

'The opposite end of the housing 28 is provided with anannular flange 36 which seats upon a support 37 and is secured to the latter by suitable means such as screws 38. 'The support 37 has 'an opening therein through The opening is surrounded by a ring 39 having a seal 40 bearing against the shaft 12, the ringbeing held in place by screws 41.

The support 37 has an inwardly directed flange 42 which 'carries another seal'43 that bears against the shaft 12, and

between the seals 40 and 43 is a bearing assembly 44.

The support 37 includes an annular boss 45 which surrounds the shaft-accommodating opening. Within the boss 45 is an annular chamber 46 in which is mounted a pair of inter-fitting washers 47 and 48 and between which is a sealing ring 49. The washer 48 bears against a .ring 50 held against the boss 45 'by screws 51 and the washer 47 is lightly urged toward the washer 48, so as to compress the seal 49, by means of a spring 52 reacting between the support 37 and the washer 47.

The centrifuge .1 is adapted to be rotated about its longitudinal axis and means for rotating the centrifuge includes an electric motor 53 having a driven pulley 54 around which is trained a belt 55, the belt also being trained around a pulley 56 fixed on the shaft 9a.

Means is provided for introducing fluid to the centrifuge and comprises a hollow tube 57 that extends through the hollow shaft 9a and is connected to a source (not shown) of fluid to be treated. Means for receiving fluid from the centrifuge after treatment comprises a block 58 mounted on the support 37 by the screws 51 and having a counterbore 59in communication with the passageway 24. The counterbore 59 communicates with a port 60 formed in the block 58 and the port receives a theaded discharge pipe or tube 61. The block 58 is provided with another port 62 which communicates with the passageway 16 and receives a threaded discharge pipe or tube 63. A packing 64 is provided between the shaft 15 and the block 58 in the vicinity of the port 62 and on opposite sides of a ported ring 65 through which fluid passes from the passageway 16 to the port 62. The packing 64 is maintained in proper position bya clamp ring 66 that is adjustably mounted on the block 58 by means of screws 67.

In the operation of the apparatus thus far described, fluid to be clarified is introduced via the pipe 57 to the chamber 18a during rotation of the centrifuge. Because it is introduced with whirling grooves it is immediately accelerated to the speed of rotation of the unit and the slippage factor is insignificant. Fluid in the chamber 18a is hurled radially outwardly by centrifugal force. Part of the fluid enters the passages 26a and the remaining part of the fluid enters the passages 26b. As the centrifuge continues to rotate, the fluid in the passages 26a and 26b is acted on by centrifugal force and is caused to be driven axially of the centrifuge, due to the pitch of the passages. Continued application of centrifugal force will cause the more dense components of the fluid to be driven radially outwardly, displacing the less dense components radially inwardly. As the fluid progresses axially of the centrifuge and reaches the zone of the baffle 20, the more dense components will have been segregated in the passages 26b and the less dense components will have been segregated in the passages 26a. The more dense components will enter the passageway 25 and pass through the passages 23 and 24 through the port 60 and into the discharge pipe 61. The less dense components will enter the passageway 17 for delivery to the discharge pipe 63 through the passageway 16, through the ported ring 65, and through the port 62.

The resident time of the fluid in the centrifuge will depend upon the pressure at which the fluid is fed to the centrifuge, the speed of rotation of the centrifuge, and the linear distance of the passages of the centrifuge as determined by the pitch of the threads. The pressure at which the fluid is fed will depend to some degree on whether the centrifuge is horizontal or vertical, and it may varyfrom static head pressure to any desired amount. The speed of rotation of the centrifuge also may vary within wide limits. It has been found, however, that rotation of the centrifuge at a speed sufiicient to create centrifugal forces about 10,000 times gravity is adequate for the clarifying of most fluids, including liquids and gases.

Another way in which the retention time of the fluid can be controlled is by the use of progressive or regressive grooving of the parts 2 and 3 and by Varying the length of the parts 2.and 3.

Certain advantages can be achieved as a result of the closed housing 28. For example, air from within the housing can be exhausted so as to reduce skin friction during rotation of the centrifuge. Moreover, the housing lends itself to the employment of heat or refrigeration in those instances where desired.

The centrifuge 1a disclosed in FIGURE 3 is designed primarily for the mixing of different density fluids, but includes many parts which are similar to those previously described. Such parts are indicated by similar reference characters. One of the differences between the embodiment shown in FIGURE 1 and the embodiment shown in FIGURE 3 is that the latter includes a baflle 19a similar to the baffle 19, with the exception that the baffle 19a includes a conical end wall 70 that is fixed to the intake pipe 57, the pipe 57 being surrounded by a considerably larger intake pipe 71 for a purpose presently to be explained. The embodiment of FIGURE 3 includes a cylinder member 3a which differs from the cylinder 3 previously described in that the threads or grooves formed on the cylinder 3a are of the opposite hand from the hand of the threads formed on the shell 2. Thus, if the threads formed in the bore of the shell 2 are left hand threads, the threads formed on the cylinder will be right hand threads. The significance of this construction will be pointed out subsequently.

When assembling the parts 2 and 3a, the bottom wall 14 of the cylinder is spaced from the bottom wall 11 of the shelf by the lugs 18b as before so as to provide the passageway 23 therebetween and the concial end wall 13 of the cylinder 3a is spaced from the wall 70 of the baflie 19a by lugs 18' on the wall 13 so as to provide a passageway 72 therebetween. The battle 19a is so positioned within the shell 2 as to provide a passageway 73 between the baflie wall 70 and the end bell 9 of the shell, lugs 18 being provided on the wall 9 as previously.

In the operation of the apparatus disclosed in FIGURE 3, different density fluids to be mixed are introduced to the respective passageways 72 and 73 through the inlet pipes 57 and 71. The more dense fluid is introduced to the passageway 72 through the inlet pipe 57 and the less dense fluid is introduced to the passageway 73 through the pipe 71. The fluids are hurled radially by centri- 'fugal force toward the periphery of the centrifuge, but

it will be noted that the more dense fluid will be radially inward of the less dense fluid at the inlet end of the centrifuge.

Initially, the more dense fluid will enter the radially inner passages 26a and the less dense fluid will enter the radially outer passages 26b. When the fluids progress to the terminal end of the baffle 19a, or earlier if the baffle is perforated, they will be in a position to mingle with one another. Since the more dense fluid is radially inwardly of the less dense fluid, the more dense fluid will seek to move radially outwardly to occupy the passages 26b and displace the less dense fluid from those passages to the passages 26a. Due to the opposite hand grooves on the respective members 2 and 3a, the continuous passages 26a and 26b do not form one continuous spiral passage like the passage 26 previously described. Instead, there will be a multiplicity of generally pyramidal shaped pockets where the nodes of the respective threads intersect one another. Consequently, the transposition of the more dense and less dense fluids creates a turbulence and shearing between the two fluids which produces a thorough mixing of the two fluids. By the time the fluids have reached the discharge end of the centrifuge, the two fluids will be thoroughly mixed and can be discharged together through the passageway 23.

The centrifuge 1b illustrated in FIGURE 4 combines the characteristics of each of the centrifuges 1 and 1a. Again, the parts of the apparatus shown in FIGURE 4 which are similar to previously described parts are indicated by similar reference characters. For all practical purposes, the shell 2a disclosed in FIGURE 4 is the same as the shells previously described. The only difference of any significance is that the bore of the shell 2a is provided with an annular radial groove 74 about midway between its ends for a purpose to be explained.

The cylinder 311 includes a first threaded section 75 and a second elongated section 76 spaced from one another by an annular radial groove 77 that is coplanar with the groove 74. The hand of the threads or grooves formed on the section 75 is opposite to the hands of the threads formed on the shell 2a, and the hand of the threads on the cylinder section 76 is the same as the hand of the threads formed on the shell 2a. For example, if the threads formed on the shell 2a are right hand threads, then the threads on the cylinder section 75 will be left hand threads and the threads on the cylinder section 76 will be right hand threads. Shell 3b is supported from wall 21 by lugs 18b on the wall 14 and the lugs 1812 on the wall 11 support the wall 21.

The apparatus disclosed in FIGURE 4 is designed to mix different density fluids to obtain a chemical reaction therebetween and then to clarify the resulting components of the reaction. In the operation of the apparatus, more dense fluid is introduced through the inlet pipe 57 to the passageway 72 during rotation of the centrifuge for introduction to the radially inner passages 26a. Less dense fluid simultaneously is introduced through the inlet pipe 71 to the passageway 73 for introduction to the radially outer passages 26b. Continued rotation of the centrifuge 111 will cause the fluids to mix together in the same manner described in connection with the apparatus shown in FIGURE 3, until such time as the mixture reaches the grooves 74 and 77. From the grooves 74 and 77 the mixture will be driven through the passages 26 and clarified according to the densities of its component parts, the more dense components being driven radially outwardly of the less dense components for delivery to the passageways 23 and 17, respectively, in the same manner as was described in connection with the embodiment shown in FIGURE 1.

This disclosure is representative of presently preferred apparatus and methods, but is intended to be illustrative rather than definitive thereof. The invention is defined in the claims.

I claim:

1. Fluid treating apparatus comprising a first tubular member; a second member concentrically mounted within said first member and having an outer diametral size corresponding substantially to the inner diametral size of said first member, the confronting surface of each of said members being helically grooved from end to end to form radially inner and radially outer fluid passages between said members in communication with each other over substantially the full length of said passages; means at one end of said member for introducing fluid to said passages; means at the opposite end of said members for re ceiving fluid from said passages; annular sleeve means interposed between and in engagement with the confronting surfaces of said members at least at one end of said members for separating said inner and outer passages from each other; and means connected to one of said members for rotating both of said members conjointly and at the same speed.

2. The construction set forth in claim 1 wherein said sleeve means is imperforate.

3. The construction set forth in claim 2 including independent fluid conduit means in communication with each of said passages at said one end of'said members.

4. The construction set forth in claim 1 wherein said sleeve means is perforated.

5. The construction set forth in claim 1 wherein the helical grooves formed in said members are formed at the same pitch.

6. The construction set forth in claim 1 wherein the helical grooves formed in said members are of the opposite hand.

7. The construction set forth in claim 1 wherein the helical grooves formed in said members are partly of the same hand and partly of the opposite hand.

8. The construction set forth in claim 1 wherein each end of said members is provided with said sleeve means.

9. The construction set forth in claim 8 including independent fluid conduit means in communication with each of said passages at least at one end of said members.

10. Fluid treating apparatus comprising a centrifuge rotatable about an axis of rotation, said centrifuge having a first continuous fiuid passage therein spiraling about said axis in one direction from one end of said centrifuge to the other, a second continuous fluid passage therein spiraling about said axis in the opposite direction from said one end of said centrifuge to a zone intermediate the ends thereof, and a third continuous fluid passage therein spiraling about said axis in said one direction from said zone to said other end of said centrifuge, said first'fluid passage being contiguous to and in communication with said second and third fluid passages.

11. A method of mixing fluids of different densities comprising introducing diflerent density fluids to a rotatable centrifuge having radially inner and radially outer spiraling passages, the more dense fluid being introduced to the radially inner passages; rotating said centrifuge at a speed to effect movement of said fluids radially outwardly and spirally along their passages; mingling said fluids in said passages during rotation of said centrifuge whereby the more dense fluid and the less dense fluid form ,a mixture; and collecting the mixture of fluids.

12. A method of mixing fluids of different densities comprising introducing different density fluids to one end of a rotatable centrifuge having radially inner and radially outer spiraling passages therein in communication with each other, the more dense fluid being introduced to the radially inner passages; rotating said centrifuge at a speed to effect movement of said fluids radially outwardly and spirally along their passages toward the opposite end of said centrifuge; mingling said fluids in said passages during rotation of said centrifuge whereby the more dense fluid and the less dense fluid form a mixture; clarifying the mixture adjacent said opposite end of said centrifuge into more dense and less dense parts; and separately collecting said, parts from said opposite end of said centrifuge.

'8 References Cited by the Examiner UNITED .STATES PATENTS 624,424 5/1899 Bertram 23341 745,083 11'/1903 Stussy 2331 764,489 7/1904 McLeod 23337 900,446 10'/ 1908 Stussy 2333 1,061,656 5/1913 Black 23319 1,064,184 6/1913 Wels 2331 4 X 1,492,498 4/1924 Wait 23252 1,575,116 3/1926 Jones 2331'4 1,602,752 10/1926 Cuthbert 23329 2,044,996 6/1936 Podbielniak 2331 2,512,471 6/1950 Trist. 2,547,151 '4/ 1951 Braeseke 2593 X 2,688,437 9/1954 Monnet 23346 X 2,705,594 4/1955 Brewer 23315 2,730,299 1/ 1956 Kelsey 2333 2,838,290 6/1958 'Simpson 2593 2,869,837 1/1959 'Pickin 259'3 2,900,129 8/1959 Dega 23328 2,904,407 9/1959 Rosenthal et al. 23-252 3,022,937 2/1962 Dega 23328 3,074,627 1/1963 Goetz 233-46 X 3,108,953 10/1963 Palmqvist et a1. 23315 3,129,175 4/1964 Jones 23328 FOREIGN PATENTS 842,692 7/ 1960 Great Britain. 855,359 11/1960 Great Britain.

M. CARY NELSON, Primary Examiner.

HERBERT L. MARTIN, ROBERT F. BURNETT,

HARRY -B. THORNTON, Examiners. 

1. FLUID TREATING APPARATUS COMPRISING A FIRST TUBULAR MEMBER; A SECOND MEMBER CONCENTRICALLY MOUNTED WITHIN SAID FIRST MEMBER AND HAVING AN OUTER DIAMETRAL SIZE CORRESPONDING SUBSTANTIALLY TO THE INNER DIAMETRAL SIZE OF SAID FIRST MEMBER, THE CONFRONTING SURFACE OF EACH OF SAID MEMBERS BEING HELICALLY GROOVED FROM END TO END TO FORM RADIALLY INNER AND RADIALLY OUTER FLUID PASSAGES BETWEEN SAID MEMBERS IN COMMUNICATION WITH EACH OTHER OVER SUBSTANTIALLY THE FULL LENGTH OF SAID PASSAGES; MEANS AT ONE END OF SAID MEMBER FOR INTRODUCING FLUID TO SAID PASSAGES; MEANS AT THE OPPOSITE END OFF SAID MEMBERS FOR RECEIVING FLUID FROM SAID PASSAGES; ANNULAR SLEEVE MEANS INTERPOSED BETWEEN AND IN ENGAGEMENT WITH THE CONFRONTING SURFACES OF SAID MEMBERS AT LEAST AT ONE END OF SAID MEMBERS FOR SEPARATING SAID INNER AND OUTER PASSAGES FROM EACH OTHER; AND MEANS CONNECTED TO ONE OF SAID MEMBERS FOR ROTATING BOTH OF SAID MEMBERS CONJOINTLY AND AT THE SAME SPEED. 